Connection Refused on Port 9000 for Logstash Deployment on Kubernetes - kubernetes

Question

I'm attempting to use the Statistics Gathering Jenkins plugin to forward metrics to Logstash. The plugin is configured with the following url: http://logstash.monitoring-observability:9000. Both Jenkins and Logstash are deployed on Kubernetes. When I run a build, which triggers metrics forwarding via this plugin, I see the following error in the logs:
2022-02-19 23:29:20.464+0000 [id=263] WARNING o.j.p.s.g.util.RestClientUtil$1#failed: The request for url http://logstash.monitoring-observability:9000/ has failed.
java.net.ConnectException: Connection refused
at java.base/sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at java.base/sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:777)
at org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.processEvent(DefaultConnectingIOReactor.java:173
I get the same behavior when I exec into the jenkins pod and attempt to curl logstash:
jenkins#jenkins-7889fb54b8-d9rvr:/$ curl -vvv logstash.monitoring-observability:9000
* Trying 10.52.9.143:9000...
* connect to 10.52.9.143 port 9000 failed: Connection refused
* Failed to connect to logstash.monitoring-observability port 9000: Connection refused
* Closing connection 0
curl: (7) Failed to connect to logstash.monitoring-observability port 9000: Connection refused
I also get the following error in the logstash logs:
[ERROR] 2022-02-20 00:05:43.450 [[main]<tcp] pipeline - A plugin had an unrecoverable error. Will restart this plugin.
Pipeline_id:main
Plugin: <LogStash::Inputs::Tcp port=>9000, codec=><LogStash::Codecs::JSON id=>"json_f96babad-299c-42ab-98e0-b78c025d9476", enable_metric=>true, charset=>"UTF-8">, host=>"jenkins-server.devops-tools", ssl_verify=>false, id=>"0fddd9afb2fcf12beb75af799a2d771b99af6ac4807f5a67f4ec5e13f008803f", enable_metric=>true, mode=>"server", proxy_protocol=>false, ssl_enable=>false, ssl_key_passphrase=><password>>
Error: Cannot assign requested address
Exception: Java::JavaNet::BindException
Stack: sun.nio.ch.Net.bind0(Native Method)
Here is my jenkins-deployment.yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: jenkins
namespace: devops-tools
labels:
app: jenkins-server
spec:
replicas: 1
selector:
matchLabels:
app: jenkins-server
template:
metadata:
labels:
app: jenkins-server
spec:
securityContext:
fsGroup: 1000
runAsUser: 1000
serviceAccountName: jenkins-admin
containers:
- name: jenkins
env:
- name: LOGSTASH_HOST
value: logstash
- name: LOGSTASH_PORT
value: "5044"
- name: ELASTICSEARCH_HOST
value: elasticsearch-logging
- name: ELASTICSEARCH_PORT
value: "9200"
- name: ELASTICSEARCH_USERNAME
value: elastic
- name: ELASTICSEARCH_PASSWORD
value: changeme
image: jenkins/jenkins:lts
resources:
limits:
memory: "2Gi"
cpu: "1000m"
requests:
memory: "500Mi"
cpu: "500m"
ports:
- name: httpport
containerPort: 8080
- name: jnlpport
containerPort: 50000
livenessProbe:
httpGet:
path: "/login"
port: 8080
initialDelaySeconds: 90
periodSeconds: 10
timeoutSeconds: 5
failureThreshold: 5
readinessProbe:
httpGet:
path: "/login"
port: 8080
initialDelaySeconds: 60
periodSeconds: 10
timeoutSeconds: 5
failureThreshold: 3
volumeMounts:
- name: jenkins-data
mountPath: /var/jenkins_home
volumes:
- name: jenkins-data
persistentVolumeClaim:
claimName: jenkins-pv-claim
Here is my jenkins-service.yaml
apiVersion: v1
kind: Service
metadata:
name: jenkins-server
namespace: devops-tools
annotations:
prometheus.io/scrape: 'true'
prometheus.io/path: /
prometheus.io/port: '8080'
spec:
selector:
app: jenkins-server
k8s-app: jenkins-server
type: NodePort
ports:
- port: 8080
targetPort: 8080
nodePort: 30000
Here is my logstash-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: logstash-deployment
namespace: monitoring-observability
labels:
app: logstash
spec:
selector:
matchLabels:
app: logstash
replicas: 1
template:
metadata:
labels:
app: logstash
spec:
containers:
- name: logstash
env:
- name: JENKINS_HOST
value: jenkins-server
- name: JENKINS_PORT
value: "8080"
image: docker.elastic.co/logstash/logstash:6.3.0
ports:
- containerPort: 9000
volumeMounts:
- name: config-volume
mountPath: /usr/share/logstash/config
- name: logstash-pipeline-volume
mountPath: /usr/share/logstash/pipeline
volumes:
- name: config-volume
configMap:
name: logstash-configmap
items:
- key: logstash.yml
path: logstash.yml
- name: logstash-pipeline-volume
configMap:
name: logstash-configmap
items:
- key: logstash.conf
path: logstash.conf
Here is my logstash-service.yaml
kind: Service
apiVersion: v1
metadata:
name: logstash
namespace: monitoring-observability
labels:
app: logstash
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "logstash"
spec:
selector:
app: logstash
ports:
- protocol: TCP
port: 9000
targetPort: 9000
type: ClusterIP
Here is my logstash configmap:
apiVersion: v1
kind: ConfigMap
metadata:
name: logstash-configmap
namespace: monitoring-observability
data:
logstash.yml: |
http.host: "0.0.0.0"
path.config: /usr/share/logstash/pipeline
logstash.conf: |
input {
tcp {
port => "9000"
codec => "json"
host => "jenkins-server.devops-tools"
ssl_verify => "false"
}
}
filter {
if [message] =~ /^\{.*\}$/ {
json {
source => "message"
}
}
if [ClientHost] {
geoip {
source => "ClientHost"
}
}
}
output {
elasticsearch {
hosts => [ "elasticsearch-logging:9200" ]
}
}
There are no firewalls configured in my cluster that would be blocking traffic on port 9000. I have also tried this same configuration with port 5044 and get the same results. It seems as though my logstash instance is not actually listening on the containerPort. Why might this be?

Answer 1

I resolved this error by updating the configmap to this:
apiVersion: v1
kind: ConfigMap
metadata:
name: logstash-configmap
namespace: monitoring-observability
data:
logstash.yml: |
path.config: /usr/share/logstash/pipeline
logstash.conf: |
input {
tcp {
port => "9000"
codec => "json"
ssl_verify => "false"
}
}
filter {
if [message] =~ /^\{.*\}$/ {
json {
source => "message"
}
}
if [ClientHost] {
geoip {
source => "ClientHost"
}
}
}
output {
elasticsearch {
hosts => [ "elasticsearch-logging:9200" ]
}
}
Note that all references to the jenkins host have been removed.